Esters derived from alkanolamines, dicarboxylic acids and fatty alvohols and the cationic surfactants obtainable therefrom

ABSTRACT

Esters derived from alkanolamines, dicarboxylic acids and fatty alcohols and the cationic surfactants obtainable therefrom.  
     Novel alkanolamine esters based on the esterification reaction of alkanolamines, optionally alkoxylated, dicarboxylic acids and fatty alcohols, optionally alkoxylated, as well as the cationic surfactants and esterquats obtainable therefrom, are described.  
     The cationic surfactants and esterquats thus obtained exhibit a high degree of efficacy in softening and conditioning natural and synthetic fibres such as textiles, paper and hair, and are therefore usable in treatments for softening and conditioning the said fibres.  
     Novel aqueous fabric-softening compositions which contain the cationic surfactants and esterquats mentioned, optionally in combination with other active softening substances, are also described.

DESCRIPTION

[0001] 1. Technical Field

[0002] The present invention relates to novel esters derived fromalkanolamines, dicarboxylic acids and fatty alcohols, and to thecationic surfactants obtainable therefrom, as well as to their use assoftening agents for natural and synthetic fibres.

[0003] 2. Prior art

[0004] Cationic surfactants derived from amines have been used widelyfor some decades as softening and conditioning agents for natural andsynthetic fibres of all types, and are used in fields such as thetreatment of textile fibres and of paper and in hair hygiene products.

[0005] For ecological reasons, owing to their greater biodegradability,the use of cationic amine derivatives in which the hydrophobichydrocarbon chains are interrupted by functional ester groups has beenusual for several years, those used mostly being the quaternizedderivatives of polyalkanolamine esters, generally known as esterquats,amongst which one of the types used most is esterquats derived fromtriethanolamine, owing to their lower cost.

[0006] It is also well known that the above-mentioned esterquats areprepared from alkanolamine esters, produced previously by anesterification reaction of the alkanolamine with fatty acids orfunctionalized reactive derivatives thereof, by their quaternizationwith alkylation agents such as alkyl halides or sulphates. There is anabundant bibliography on the subject, amongst which patents or patentapplications FR-A-1593921, EP-A-239910, EP-A-295385, WO-A-9101295,DE-C-19539846 and WO-A-9849132, amongst many others, may be mentioned.

[0007] However, it is well known that esterquats are less effectivesofteners than their homologues which do not contain ester groups, andthis has led to various technical developments directed towardsimproving the softening efficacy of these esterquats.

[0008] Thus, patent U.S. Pat. No. 5,593,614 describes the improvement ofthe softening effect of esterquats by mixing them with non-ionicsurfactants, patent U.S. Pat. No. 5,501,806 proposes the mixing ofesterquats with other cationic surfactants, and patent applicationEP-A-394133 describes the use of acrylic cationic polymers as additivesfor improving softness.

[0009] British patent GB-602048 describes oligomeric alkanolamine estersbased on the esterification reaction of triethanolamine withdicarboxylic acids and fatty acids, as well as their quaternization withmethyl chloride or dimethyl sulphate and their use as softening agentsfor natural and synthetic fibres, and patents U.S. Pat. Nos. 4,719,382and 4,237,016 describe the use of the esterquats described in theabove-mentioned British patent, amongst cationic polymers of many othertypes, as additives for improving the softening efficacy of cationicsurfactants which do not contain ester groups. Moreover, patentapplication WO-A-9812293 describes the use of the same oligomericesterquats as additives for incorporation in the aqueous phase ofsoftening compositions which contain esterquats, with the object ofimproving their softening efficacy.

[0010] German patent DE-C-19539846 describes the synthesis of esterquatsderived from dicarboxylic acids, fatty acids and triethanolamnine andtheir use as hair conditioners, and patent DE-C-19715835 describesesterquats based on the reaction of methyl diethanolamine and mixturesof fatty acids and dicarboxylic acids, with subsequent ethoxylationand/or quaternization.

[0011] Patent WO-A-9849132 describes the synthesis of esterquats derivedfrom dicarboxylic acid/fatty acid/triethanolamine, within a specificselected range of proportions, and their use in fabric-softeningcompositions.

[0012] Lastly, patent DE-C-19519876 describes esterquats based on thereaction of a trialkanolamine with mixtures of fatty acids, dicarboxylicacids, and sorbitol and the subsequent quaternization and/orethoxylation of the esters produced.

[0013] However, as far as the authors of the present invention know, theprior art always relates to alkanolamine esters and to theircorresponding esterquats in which the hydrophobic chains result directlyand mainly from the esterification of fatty acids, so that nodescriptions have been found of alkanolamine esters and theircorresponding esterquats in which the hydrophobic chains result mainlyfrom fatty alcohols combined with the cationic portion of the moleculeby means of a dicarboxylic-acid bridge and which, moreover, have a highdegree of biodegradability and a greater softening efficacy than that ofconventional esterquats.

SUMMARY OF THE INVENTION

[0014] The subject of the present invention is novel esters derived fromalkanolamines, dicarboxylic acids and fatty alcohols, and the cationicsurfactants obtainable therefrom.

[0015] Also included within the subject of the present invention is theuse of the cationic surfactants based on the said esters derived fromalkanolamines, dicarboxylic acids and fatty alcohols, particularly theesterquats obtainable therefrom, as conditioning and softening agentsfor natural and synthetic fibres.

[0016] Also included within the subject of the present invention areaqueous softening compositions for textile fibres containing, either asthe active ingredient or as an additive for improving softeningefficacy, cationic surfactants based on the said esters derived fromalkanolamines, dicarboxylic acids and fatty alcohols, particularly theesterquats obtainable therefrom.

DESCRIPTION OF THE INVENTION

[0017] The alkanolamine esters of the invention are obtained by theesterification reaction of an alkanolamine of general formula (I)

[0018] with a dicarboxylic acid or with a reactive derivative thereof,of general formula (II)

HOOC—R⁴—COOH  (II)

[0019] and with a fatty alcohol, optionally alkoxylated, of generalformula (III)

[0020] in which formulae R¹ is hydrogen, a C₁-C₆ alkyl group, or theresidue

[0021] R² is a C₁-C₆ alkylene group, R³ is hydrogen or methyl, n is 0 ora whole number between 1 and 20, R⁴ is a C₁-C₃₆ alkylene group,optionally substituted or unsaturated, or an arylene group, and R⁵ is alinear or branched C₂-C₂₂ alkyl or alkenyl group.

[0022] Optionally, a fatty acid of general formula (IV) may also beincorporated in the reaction mixture

R⁶—COOH  (IV)

[0023] in which R⁶ is a linear or branched C₆-C₂₃ alkyl or alkenylgroup, an alkyl ester, a glyceride of the fatty acid, and/or a polyol,optionally alkoxylated.

[0024] The invention provides a cationic surfactant obtainable by theformation of the addition salt of the alkanolamine ester as abovedefined with mineral or organic acids.

[0025] The invention provides an esterquat obtainable by quaternizationof the alkanolamine ester as above defined by the reaction withalkylation agents.

[0026] The invention besides provides a method of treating softeningand/or conditioning treatment of natural or synthetic fiber, textile,paper fiber or hair fiber with the esterquats as above defined.

[0027] The invention further provides an aqueous fabric-softeningcomposition which comprises:

[0028] (a) a surfactant or an esterquat thereof as above shown,

[0029] (b) one or a plurality of cationic surfactants active as fabricsofteners,

[0030] (c) one or a plurality of non-ionic fabric-conditioningsurfactants,

[0031] in which the total amount of components (a), (b) and (c) isbetween 2% and 60% by weight in a manner such that, with respect to thetotal amount of the said components (a), (b) and (c),

[0032] (i) the proportion by weight of component (a) is between 2% and99%,

[0033] (ii) the proportion by weight of component (a) is between 0% and98%,

[0034] (iii) the proportion by weight of component (c) is between 0% and40%, and

[0035] (iv) the proportion by weight of the total amount of (b) and (c)is between 1% and 98%.

[0036] It is preferable that that the total amount of components (a),(b) and (c) is between 3% and 40% by weight,

[0037] (i) the proportion by weight of component (a) is between 3% and80%,

[0038] (ii) the proportion by weight of component (b) is between 0% and97%,

[0039] (iii) the proportion by weight of component (c) is between 0% and30%, and

[0040] (iv) the proportion by weight of the total amount of (b) and (c)is between 20% and 97%.

DETAILED DESCRIPTION OF INVENTION

[0041] The following may be mentioned as examples of alkanolamines whichmay be used: triethanolamine, N-methyl diethanolamine, N-methyldiisopropanolamine and triisopropanolamine, optionally alkoxylated withethylene oxide or propylene oxide, or mixtures thereof, thenon-alkoxylated alkanolamnines, particularly triethanolamine, beingpreferred.

[0042] As examples of dicarboxylic acids, without intending to providean exhaustive list, it is possible to mention succinic, malic, glutaric,adipic, sebacic, pimelic, suberic, maleic and terephthalic acids andalso those known as dimers of fatty acids or dimeric fatty acids, whichare produced by thermal oligomerization of unsaturated fatty acids, suchas those marketed by Unichema International under the name PRIPOL⁷, forexample, PRIPOL⁷ 1009, or mixtures of the said acids. Adipic acid ispreferred.

[0043] The fatty alcohols of formula (III), optionally alkoxylated withethylene oxide or propylene oxide, may be hydrogenated or nonhydrogenated fatty alcohols obtained from fats and oils of naturalorigin, for example, from tallow, palm, olive, coconut, sunflower, soya,grape marc or rape etc., non-alkoxylated alcohols which contain mainlybetween 16 and 18 carbon atoms being preferred.

[0044] Examples of fatty acids which may optionally be included in theesterification reaction are those obtained from vegetable and animaloils and fats such as those obtained from coconut, tallow, palm,sunflower, soya, olein, oil greaves, etc., optionally wholly orpartially hydrogenated, as well as purified or synthetic fatty acidssuch as lauric, stearic, palmitic, oleic, linoleic, and 2-ethylhexanoicacids, etc.

[0045] The polyols which may also optionally be included in theesterification reaction may be, for example, glycerol, pentaerythritol,sucrose, glucose, sorbitol, or glycols such as ethylene glycol,propylene glycol, diethylene glycol, dipropylene glycol, etc.

[0046] Advantageously, for the purposes of the present invention:

[0047] X the molar ratio of the dicarboxylic acid to the alkanolamine isbetween 0.2 and 1.2, preferably between 0.3 and 0.9, most preferablybetween 0.4 and 0.8,

[0048] X the molar ratio of the sum of the fatty alcohol and the fattyacid to the alkanolanine is between 0.2 and 2.0, and

[0049] X the molar ratio of the fatty acid to the fatty alcohol isbetween 0 and 10, preferably between 0.1 and 5.0, most preferablybetween 0.5 and 1.0.

[0050] X The esterification reaction is performed by methods known perse, such as that described in patent application WO-A-9849132 which isincorporated herein by reference.

[0051] The esterification reaction is preferably performed bycondensation of the dicarboxylic acid, and optionally the fatty acid,with a mixture of the alkanolamine and the fatty alcohol, and optionallythe polyol, at a temperature of between 120^(E)C and 220^(E)C, for aperiod of from 2 to 10 hours, preferably at a reduced pressure of about5 to 200 mbar and in the presence of some of the catalysts already knownfor the esterification of conventional esterquats, for example,hypophosphorous acid and paratoluene sulphonic acid, and also in thepresence of some of the usual stabilizers and antioxidants such astocopherols, BHT, BHA, citric acid, etc. The esterification reaction canalso be performed by condensing the dicarboxylic acid with thetriethanolamine in the first place and adding the fatty alcoholafterwards.

[0052] It will be clear to a person skilled in the art that theesterification reaction may alternatively also be performed by otherconventional techniques starting with reactive derivatives of thedicarboxylic acids, for example, their esters, their anhydrides, ortheir acid chlorides.

[0053] The esters thus produced are useful for preparing cationicsurfactants efficacious for use in the softening and conditioningtreatment of natural and synthetic fibres such as textiles, paper andhair. The cationic surfactants may be the esterquats obtainable by theirquaternization with alkylation agents, or addition salts of thealkanolamine esters of the invention with mineral or organic acids suchas hydrochloric, sulphuric, phosphoric, citric, and lactic acids, etc.The esterquats are preferred as cationic fibre-softening surfactants.

[0054] The esterquats are produced from the alkanolamine esters of theinvention by an additional quaternization reaction, also known per se,for example, as described in the above-mentioned patent applicationWO-A-9849132.

[0055] For example, the reaction mixture resulting from theesterification is reacted with alkylating products such as methylchloride, methyl bromide, dimethyl sulphate, diethyl sulphate, dimethylcarbonate, etc., preferably in the presence of organic solvents whichfacilitate the handling thereof, such as isopropanol, ethanol, propyleneglycol, ethylene glycol, dipropylene glycol, fatty alcohols, etc., andthe pH is subsequently adjusted to between 1.5 and 7.0, preferablybetween 2 and 4.5 by the addition of an acid such as any ofhydrochloric, sulphuric, phosphoric, citric acids, etc.

[0056] The cationic surfactants obtainable from the alkanolamine estersof the invention exhibit a high degree of fibre-softening efficacy and,moreover, owing to their degree of biodegradability, are very welltolerated from the ecological point of view. Moreover, even if the saidsurfactants are not used in a major or predominant proportion, theyconsiderably improve the softening efficacy of compositions based onconventional esterquats and other cationic surfactants and, when used asfabric softeners, counteract the adverse effect of the presence ofanionic surfactant residues in the textile fibres after washing andduring the rinsing stage.

[0057] In summary, the cationic surfactants obtainable from thealkanolamine esters of the invention may be used as the basic substanceof fabric softening or hair conditioning compositions and also asadditives for softening compositions or detergents the main activecomponent of which is another cationic surfactant, or a mixturetherefrom. As well as improving the feel of the fabric, its use infabric-softening formulations facilitates ironing and reduces theappearance of creases during washing and its use in hair-conditioningcompositions or as an additive in shampoos improves combability and theappearance of the hair.

[0058] With some of the products defined in this patent, particularlythose in which the fatty chains have unsaturated bonds, it is possibleto produce softening formulations which are translucent or transparentwithout the need to use the solvents usually used for formulas of thistype.

[0059] In particular, although not exclusively, the present inventionincludes aqueous fabric-softening compositions which contain:

[0060] (a) cationic surfactants or esterquats obtainable from thealkanolamine esters of the invention,

[0061] (b) one or a plurality of cationic surfactants active as fabricsofteners,

[0062] (c) one or a plurality of non-ionic fabric-conditioningsurfactants,

[0063] in which the total amount of components (a), (b) and (c) isbetween 2% and 60% by weight, in a manner such that, with respect to thetotal amount of the said components (a), (b) and (c),

[0064] (i) the proportion by weight of component (a) is between 2% and100%,

[0065] (ii) the proportion by weight of component (b) is between 0% and98%, and

[0066] (iii) the proportion by weight of component (c) is between 0% and40%,

[0067] the remaining constituents being water and other optionalconstituents selected from amongst those normally used in aqueousfabric-softening compositions.

[0068] Preferably, the aqueous fabric-softening compositions of theinvention contain between 3% and 40% by weight of the total amount ofcomponents (a), (b) and (c) in a manner such that, with respect to thetotal amount of the said components (a), (b) and (c),

[0069] (i) the proportion by weight of component (a) is between 3% and80%,

[0070] (ii) the proportion by weight of component (b) is between 0% and97%, and

[0071] (iii) the proportion by weight of component (c) is between 0% and30%, the remaining constituents being water and other optionalconstituents selected from amongst those usually used in aqueousfabric-softening compositions.

[0072] The cationic surfactants which are active as fabric-softeners andwhich constitute component (b) of the softening compositions of theinvention are well-known to persons skilled in the art.

[0073] Amongst these may be mentioned the quaternary ammonium compoundsthe hydrophobic chains of which are not interrupted by an ester group,for example, those described in the patents U.S. Pat. Nos. 4,719,382 and4,237,016, amongst which the best known is hydrogenated tallowdialkyldimethylammonium chloride also known as DTDMAC as marketed by KAOCorporation, S.A. under the mark QUARTAMIN⁷ D86P.

[0074] However, the esterquats, descriptions of which, amongst manyothers, are to be found in the documents already cited in thisdescription, which are incorporated herein by reference, are preferredand amongst those which may be mentioned as significant examples are thefollowing:

[0075] X quaternized fatty-acid diesters with1,2-dihydroxy-3-dimethylaminopropane, as described in U.S. patent U.S.Pat. No. 4,137,180 and European patent application EP-A-0585040,

[0076] X quaternized fatty-acid diesters with N-methyl diethanolamine,such as those described in French patent application FR-A-1593921 and inEuropean patent EP-B-0239910, for example, hydrogenated tallow diesterquaternized with methyl chloride, marketed by KAO Corporation, S.A.under the mark KAOSOFT⁷ PH,

[0077] X salts of fatty-acid amidoesters with N-methyl-N-aminopropylethanolamine, for example, that marketed by KAO Corporation under themark KAOSOFT⁷ 1,

[0078] X quaternized fatty-acid diesters with triethanolamine, such asthose described in U.S. patent U.S. Pat. No. 3,915,867 and in a largenumber of subsequent patents, for example, diesters of partiallyhydrogenated tallow quaternized with dimethyl sulphate, which aremarketed by KAO Corporation, S.A. under the marks TETRANYL⁷ AT-7590 andTETRANYL⁷ L1/90.

[0079] It should be pointed out that, when the term “diester” isreferred to, it is intended to indicate that the diester is a majorconstituent of the mixture, although the product may still containvariable quantities of monoester compounds and, in the case oftriethanolamine, of triester compounds.

[0080] Also included in this consideration of cationic surfactants of asoftening nature are the oligomeric cationic surfactants described inpatent application WO-A-9849132, for example, those marketed by KAOCorporation S.A. under the references TETRANYL⁷ PH-2 and TETRANYL⁷ PH-5.

[0081] The fabric-conditioning non-ionic surfactants which constitutecomponent (c) are also well known to persons skilled in the art andamongst them may be mentioned: fatty acids, fatty-acid esters,particularly linear or branched C₈-C₁₈ fatty-acid esters, alkoxylated orwithout alkoxylation, Guerbet alcohols alkoxylated or withoutalkoxylation, glycerol esters, sorbitan esters alkoxylated or withoutalkoxylation, for example, KAOPAN⁷ marketed by KAO Corporation, S.A.,sucrose esters, C₈₋₁₈ fatty alcohols, glycerol esters, optionallyalkoxylated, for example, LEVENOL⁷ marketed by KAO Corporation, S.A.,and pentaerythritol esters, alkoxylated or without alkoxylation.

[0082] Insofar as other optional components are referred to, although itshould not be considered as an exhaustive description of all of thepossibilities which, on the other hand, are well known to personsskilled in the art, the following may be mentioned:

[0083] a) Other products which improve the performance of the softeningcompositions, such as silicones, amine oxides, anionic surfactants suchas lauryl ether sulphate or lauryl sulphate, amphoteric surfactants suchas cocoamidopropyl betaine or the alkylbetaines, sulphosuccinates,polyglucosidate derivatives, etc.

[0084] b) Stabilizers such as salts of short-chain amines, quaternizedor without quaternization, for example, of triethanolamine, N-methyldiethanolamine, etc., and also non-ionic surfactants such as ethoxylatedfatty alcohols, ethoxylated fatty amines, ethoxylated alkylphenols, etc.

[0085] c) Products which improve viscosity control, for example,inorganic salts such as calcium chloride, magnesium chloride, calciumsulphate, sodium chloride, etc.; products which serve to reduceviscosity in concentrated compositions, such as glycol compounds, forexample, ethylene glycol, dipropylene glycol, polyglycols, etc., andthickening agents for diluted compositions, for example, polymersderived from cellulose, guar gum, etc.

[0086] d) Components for adjusting the pH, which is preferably between1.5 and 4.5, such as inorganic and/or organic acids of any type, forexample, hydrochloric, sulphuric, phosphoric, and citric acids, etc.

[0087] e) Agents which improve “soil release”, such as the knownterephthalate-based polymers or copolymers.

[0088] f) Bactericidal preservatives such as formol, Kathon GC,Bronopol, etc.

[0089] g) Other products such as antioxidants, colouring substances,perfumes, germicides, fungicides, anticorrosive agents, anti-creasingagents, opacifiers, optical brightening agents, pearlizing agents, etc.

[0090] The softening compositions may be produced simply by mixing theirconstituents until they are dispersed or dissolved, with the use ofmethods well known to persons skilled in the art.

[0091] The following examples are given in order to provide a personskilled in the art with a sufficiently clear and complete explanation ofthe present invention but should not be considered as limiting of theessential aspects of its subject, as set out in the preceding portionsof this description.

EXAMPLES Examples 1 to 16 Preparation of the Alkanolamine Esters

[0092] The products of Table 1 were prepared with the use of thereagents and the quantities indicated in Table 1, in accordance with thefollowing general esterification method:

[0093] The alkanolamnine and the fatty alcohol and, where appropriate,the polyol, were mixed in a reaction flask equipped with a stirrer, atemperature probe and an inlet for an inert gas. The following are addedas esterification catalysts: 50% by weight hypophosphorous acid insufficient quantity to give a content of 1000 ppm relative to the totalload or, alternatively, paratoluene sulphonic acid in sufficientquantity to give a content of 500 ppm relative to the total load. Themixture was heated to 100^(E)C in an inert atmosphere, the dicarboxylicacid and, where appropriate, the fatty acid, were added, the temperaturewas increased to 170^(E)C, and this temperature was maintained whilstthe esterification water was distilled until the acidity index of themixture was below 5 mg KOH/g.

[0094] Where appropriate, the esterification product will be subjectedto a conventional ethoxylation reaction with ethylene oxide. TABLE 1Reagents used in the esterification reaction Dicarboxylic Fatty alcoholor Fatty acid or Ex. Amine acid source therefor source therefor Polyol 1TEA Adipic Hydrogenated tallow — — (1 Mole) (0.5 Moles) (0.6 Moles) 2TEA Adipic Hydrogenated tallow — — (1 Mole) (0.7 Moles) (1.2 Moles) 3TEA Adipic Hydrogenated tallow Tallow — (1 Mole) (0.8 Moles) (0.2 Moles)(0.6 Moles) 4 TEA Adipic Hydrogenated tallow Tallow — (1 Mole) (0.5Moles) (0.2 Moles) (0.5 Moles) 5 TEA Adipic Hydrogenated tallow Coconut— (1 Mole) (0.5 Moles) (0.2 Moles) (0.5 Moles) 6 TEA Adipic Hydrogenatedtallow Oleic — (1 Mole) (0.7 Moles) (0.1 Moles) (0.9 Moles) 7 TEA AdipicPalm — — (1 Mole) (0.6 Moles) (0.8 Moles) 8 TEA Adipic Hydrogenatedtallow — — (1 Mole) (0.7 Moles) (0.4 Moles) 9 TEA Adipic Hydrogenatedtallow 2-ethylhexanoic — (1 Mole) (0.8 Moles) (0.3 Moles) (0.8 Moles) 10TEA PRIPOL⁷ 1009 Oleic Coconut — (1 Mole) (0.3 Moles) (0.2 Moles) (0.8Moles) 11 TEA Adipic Hydrogenated tallow Tallow Glycerol (1 Mole) (0.5Moles) (0.1 Moles) (0.6 Moles) (0.5 Moles) 12 TEA Adipic Hydrogenatedtallow Tallow Sorbitol (1 Mole) (0.6 Moles) (0.2 Moles) (0.8 Moles)(0.25 Moles) 13 TEA Adipic Hydrogenated tallow Tallow — (1 Mole) (0.4Moles) (0.5 Moles) (0.6 Moles) 14 TEA Adipic Hydrogenated tallow Tallow— (1 Mole) (0.6 Moles) ethoxylated (5EO) (0.8 Moles) (0.2 Moles) 15 TEAAdipic Hydrogenated tallow Tallow — (1 Mole) (0.8 Moles) (0.1 Moles)(0.5 Moles) 16 Product obtained in Example 4 subsequently ethoxylatedwith 3 moles of EO

[0095] The product obtained in the esterification, which constitutes thesubject of the invention, is a very complex mixture of chemicalcompounds and is useful, in crude form as it is produced, for preparingthe cationic surfactants and esterquats which are also subjects of theinvention.

Example 17 Preparation of the Surfactant Addition Salts

[0096] The esterification product of Example 6 was loaded, together withthe quantity of isopropyl alcohol sufficient to give a content of 15%thereof, relative to the total load, and the quantity of BHT necessaryto give a content of 500 ppm relative to the total load, into a reactionflask equipped with a stirrer, a temperature probe, and a droppingfunnel. The mixture was heated to 50^(E)C and a 30% solution ofhydrochloric acid was added to it, over a period of 1 hour, in thestoichiometric quantity necessary to salify all of the product, stirringbeing continued at a temperature of 50^(E)-55^(E)C for a further 1-2hours.

[0097] The addition salts of other esterification products can beobtained in a similar manner either with hydrochloric acid or withother, different acids.

Examples 18 to 32 Preparation of the Esterquats

[0098] The esterquats of Table 2 were prepared with the use of thereagents indicated in Table 2, in accordance with the following generalquaternization methods:

[0099] Quaternization with methyl chloride.—The product resulting fromthe esterification step, together with sufficient quantity of isopropylalcohol for the said alcohol to represent between approximately 8% andapproximately 12% by weight relative to the crude quaternized productand, optionally, BHT in the quantity necessary to give a content of 500ppm relative to the total load, were loaded into a reaction flaskcapable of working under pressure conditions and equipped with astirrer, a dropping funnel, and a temperature probe. The mixture washeated to 85^(E)-90^(E)C and a quantity slightly greater than thestoichiometric quantity of methyl chloride was added, whilst thepressure was kept between 2 and 3 kg/cm². Upon completion of theaddition of the methyl chloride, stirring of the reaction mixture wascontinued for 1-2 hours at 80^(E)-85^(E)C.

[0100] Quaternization with dimethyl sulphate.—The product resulting fromthe esterification step, together with sufficient quantity of isopropyland/or ethyl alcohol to represent between approximately 8% andapproximately 12% by weight relative to the finished product and,optionally, BHT in sufficient quantity to give a content of 500 ppmrelative to the total load, were loaded into a 1-litre reaction flaskequipped with a stirrer, a temperature probe, and a dropping funnel. Themixture was heated to 50^(E)C and a quantity slightly less than thestoichiometric quantity of dimethyl sulphate was added slowly over 1-2hours. Upon completion of the addition, stirring of the reaction mixturecontinued for a further 3-4 hours at 50^(E)-55^(E)C. TABLE 2 Reagentsused in the quaternization reaction. Example Alkanolamine esterAlkylation agent 18 that obtained in Example 1 Dimethyl sulphate 19 thatobtained in Example 2 Methyl chloride 20 that obtained in Example 3Dimethyl sulphate 21 that obtained in Example 4 Dimethyl sulphate 22that obtained in Example 5 Dimethyl sulphate 23 that obtained in Example7 Dimethyl sulphate 24 that obtained in Example 8 Dimethyl sulphate 25that obtained in Example 9 Methyl chloride 26 that obtained in Example10 Dimethyl sulphate 27 that obtained in Example 11 Dimethyl sulphate 28that obtained in Example 12 Dimethyl sulphate 29 that obtained inExample 13 Dimethyl sulphate 30 that obtained in Example 14 Dimethylsulphate 31 that obtained in Example 15 Dimethyl sulphate 32 thatobtained in Example 16 Dimethyl sulphate

[0101] The esterquats thus obtained are also very complex mixtures ofchemical compounds and are useful, in crude form as they are produced,for the preparation of compositions for softening and conditioningnatural and synthetic fibres.

Example 33 Softness Tests on Fabrics

[0102] Softness tests of the cationic surfactants produced in accordancewith the examples given above, as well as comparative tests performedwith other, conventional cationic surfactants, were performed inconditions similar to those of actual use, by comparing the resultsobtained with doses corresponding, with two ratios of active softeningsubstance in relation to the weight of textile fibre, that is: 0.1% and0.2% by dry weight of solid active softening substance, relative to theweight of the fabric.

[0103] The tests were performed on cotton towels, by performing fivewashing operations and five softening operations, at the rinsing stage,one after each wash, with the use of water of 25^(E) HF (French degreesof hardness) in a MIELE⁷ washing machine and with the use of thedetergent sold on the Spanish market by the company Benckiser, under thetrademark COLON⁷.

[0104] The results were evaluated by calculation of the statistical meanof the values obtained on the basis of the quantification of thesubjective opinion of twenty experienced panellists who used asreferences: a) a blank, consisting of a cotton towel which was nottreated with softener after washing, to which the value 0 was assigned,and b) a control which was assigned the value 10, corresponding to thesoftness result achieved with the product QUARTAMIN⁷ D86P marketed byKAO Corporation, S.A., which is hydrogenated tallowdialkyldimethylammonium chloride, a conventional quaternary softeningcompound recognized as highly effective, although with poorer ecologicaltolerance owing to the fact that it has no ester groups intercalated inits hydrophobic chains. The results obtained are shown in Table 3. TABLE3 Softness tests on fabrics. Active softening substance SoftnessAlkanolamine ester salt of Example 17 8 Esterquat of Example 18 9Esterquat of Example 19 8 Esterquat of Example 21 9 Esterquat of Example29 8 Esterquat of Example 30 9 Esterquat of Example 32 8 QUARTAMIN⁷ D86P(comparative control) 10  TETRANYL⁷ AT-7590 7

[0105] It can clearly be inferred from the results set out in Table 3that the active softening substances composed of the cationicsurfactants of the invention provide a softening efficacy superior tothat of conventional esterquats and, in some cases, close to thatachieved with the control product which is generally recognized for itshigh degree of softening efficacy.

Examples 34 to 50 Aqueous Fabric-Softening Compositions

[0106] The softening compositions set out in Table 4, in which thepercentages indicated are relative to the total weight of thecomposition, were prepared by conventional stirring and mixing methods.The softening efficacy of the compositions was evaluated by the methoddescribed in Example 31. TABLE 4 TETRANYL⁷ AT-7590 is a conventionalesterquat derived from triethanolamine, marketed by KAO Corporation,S.A. TETRANYL⁷ L1-90 is a conventional esterquat derived fromtriethanolamine, marketed by KAO Corporation, S.A. KAOSOFT⁷ PH is aconventional esterquat derived from methyl diethanolamine, marketed byKAO Corporation, S.A. KAOSOFT⁷ 1 is an amidoester marketed by KAOCorporation. TETRANYL⁷ PH-5 is a cationic oligomeric product marketed byKAO Corporation, S.A. QUARTAMIN⁷ D86P is a hydrogenated tallow dialkyldimethyl- ammonium chloride marketed by KAO Corporation, S.A. LEVENOL⁷C-421 is an ethoxylated glycerol ester marketed by KAO Corporation, S.A.KAOPAN⁷ SP-120 is a sorbitan ester marketed by KAO Corporation, S.A.

[0107] TABLE 4 Aqueous fabric-softening compositions and their softeningefficacy. Minority constituents^(B) Ex. Active softening substance^(A)Non-ionic surfactant Cl₂Mg and water Softness 34 Esterquat Example 18(2.5%) — — to 100% 9 TETRANYL⁷ AT-7590 (2.5%) 35 Esterquat Example 19(2%) LEVENOL⁷ C-421 (4%) 0.1% to 100% 10 TETRANYL⁷ AT-7590 (14%) 36Esterquat example 20 (4%) — — to 100% 10 TETRANYL⁷ L1/90 (2.5%) 37Esterquat Example 21 (0.5%) — — to 100% 11 KAOSOFT⁷ PH (4.5%) 38Esterquat Example 22 (20%) — — to 100% 9 39 Cationic salt Example 17(2%) KAOPAN⁷ SP-120 (3%) 0.15%  to 100% 11 KAOSOFT⁷ 1 (14%) 40 Esterquatexample 23 (0.5%) — — to 100% 10 TETRANYL⁷ AT-7590 (4.5%) 41 EsterquatExample 24 (0.25%) Pentaerythritol 0.2% to 100% 8 TETRANYL⁷ AT-7590(4.75%) tetrastearate (1%) 42 Esterquat Example 25 (1%) — — to 100% 8TETRANYL⁷ AT-7590 (4%) 43 Esterquat Example 26 (2.5%) — — to 100% 9TETRANYL⁷ PH-5 (2.5%) 44 Esterquat Example 20 (1%) — — to 100% 11QUARTAMIN⁷ D86P (4%) 45 Esterquat Example 27 (5%) Glycerol — to 100% 9monostearate (1%) 46 Esterquat Example 29 (0.5%) — — to 100% 9 TETRANYL⁷AT-7590 (4.5%) 47 Esterquat Example 30 (0.25%) — — to 100% 8 TETRANYL⁷AT-7590 (4.75%) 48 Esterquat Example 31 (19.6%) — — to 100% 8 49Esterquat Example 31 (15%) — — to 100% 8 50 Esterquat Example 32 (1%) —— to 100% 8 TETRANYL⁷ AT-7590 (4%)

[0108] The softness results set out in Table 4 show that all of thecompositions exhibited a high degree of softening efficacy, and it is tobe emphasized that the use of the cationic surfactants of the inventionas additives, mixed with other active softening substances considerablyimproves their softening efficacy, particularly in the case ofconventional esterquats derived from triethanolamine and methyldiethanolamine.

[0109] Modifications which do not affect, alter, change or modify theessential aspects of the esters described are included within the scopeof the present invention.

[0110] Softener compositions described in examples 48 and 49, exhibit agood softening performance as well as a clear appearance without the useof any solvent.

1.- Alkanolamnine esters obtainable by the esterification reaction of analkanolarnine of general formula (I)

with a dicarboxylic acid or with a reactive derivative thereof, ofgeneral formula (II) HOOC—R⁴—COOH  (II) and with a fatty alcohol,optionally alkoxylated, of general formula (III)

in which R¹ is hydrogen, a C₁-C₆ alkyl group, or the residue

R² is a C₁-C₆ alkylene group, R³ is hydrogen or methyl, n is 0 or awhole number between 1 and 20, R⁴ is a C₁-C₃₆ alkylene group, optionallysubstituted or unsaturated, or an arylene group, and R⁵ is a linear orbranched C₂-C₂₂ alkyl or alkenyl group. 2.- Alkanolamine estersaccording to claim 1, characterized in that the alkanolamine of formula(I) is selected from triethanolamine, N-methyl diethanolamine, N-methyldiisopropanolamine, and triisopropanolamine, optionally alkoxylated withethylene oxide or propylene oxide, or mixtures thereof. 3.- Alkanolamineesters according to claim 1, characterized in that the dicarboxylic acidof formula (II) is selected from succinic, malic, glutaric, adipic,sebacic, pimelic, suberic, maleic, and terephthalic acids and thosewhich are obtained by thermal oligomerization of unsaturated fattyacids, or mixtures thereof. 4.- Alkanolamine esters according to claim1, characterized in that the fatty alcohols of formula (III) areselected from those derived from fats and oils of natural origin,optionally hydrogenated and/or alkoxylated. 5.- Alkanolamine estersaccording to claim 1, characterized in that the fatty alcohols offormula (III) are selected from hydrogenated or non-hydrogenated fattyalcohols derived from tallow, palm, olive, coconut, sunflower, soya,grape marc or rape, optionally alkoxylated with ethylene oxide orpropylene oxide. 6.- Alkanolamine esters according to claim 1,characterized in that a fatty acid of general formula (IV) R⁶—COOH  (IV)in which R⁶ is a linear or branched C₆-C₂₃ alkyl or alkenyl group, or analkyl ester or a glyceride of the fatty acid, and/or a polyol,optionally alkoxylated, is added to the esterification reaction mixture.7.- Alkanolamine esters according to claim 6, characterized in that thefatty acids are selected from those produced from natural oils and fats,optionally wholly or partially hydrogenated, and from purified orsynthetic fatty acids. 8.- Alkanolamine esters according to claim 6,characterized in that the fatty acids are selected from those derivedfrom coconut, tallow, palm, sunflower, soya, olives, grape marc andrape, optionally wholly or partially hydrogenated, and from lauric,stearic, palmitic, oleic, linoleic and 2-ethylhexanoic acids. 9.-Alkanolamine esters according to claim 6, characterized in that thepolyols are selected from glycerol, pentaerythritol, sucrose, sorbitol,or glycols such as ethylene glycol, propylene glycol, diethylene glycoland dipropylene glycol, all of which may be alkoxylated. 10.-Alkanolamine esters according to claim 1 or 6, characterized in that,with regard to the reagents which take part in the esterificationreaction: the molar ratio of the dicarboxylic acid to the alkanolamineis between 0.2 and 1.2, the molar ratio of the total amount of the fattyalcohol and the fatty acid to the alkanolamine is between 0.2 and 2.0,and the molar ratio of the fatty acid to the fatty alcohol is between 0and
 10. 11.- Alkanolarnine esters according to claim 10, characterizedin that the molar ratio of the dicarboxylic acid to the alkanolamine isbetween 0.3 and 0.9, preferably between 0.4 and 0.8. 12.- Alkanolamineesters according to claim 10, characterized in that the molar ratio ofthe fatty acid to the fatty alcohol is between 0.1 and 5.0, preferablybetween 0.5 and 1.0. 13.- Alkanolamine esters according to claim 1 or 6,characterized in that the esterification reaction is performed bycondensation of the dicarboxylic acid, and optionally of the fatty acid,with a mixture of the alkanolamine and the fatty alcohol, and optionallythe polyol, at a temperature of between 120^(E)C and 220^(E)C for aperiod of from 2 to 10 hours, and optionally at a reduced pressure offrom 5 to 200 mbar and in the presence of an esterification catalyst.14.- Cationic surfactants obtainable by the formation of the additionsalts of the alkanolamine esters of claim 1 or 6 with mineral or organicacids. 15.- Cationic surfactants according to claim 14, characterized inthat the mineral or organic acids are selected from hydrochloric,sulphuric, phosphoric, citric and lactic acids. 16.- Esterquatsobtainable by quaternization of the alkanolamine esters of claim 1 or 6by their reaction with alkylation agents. 17.- Esterquats according toclaim 16, characterized in that the alkylation agents are selected frommethyl chloride, methyl bromide, dimethyl sulphate, diethyl sulphate,and dimethyl carbonate. 18- A method of treating softening and/orconditioning treatment of natural or synthetic fiber, textile, paperfiber or hair fiber with the esterquats of the claim 16 or the cationicsurfactant of the claim
 14. 19.- Aqueous fabric-softening compositionswhich comprise: (a) the surfactants or esterquats of claim 14 or 16, (b)one or a plurality of cationic surfactants active as fabric softeners,(c) one or a plurality of non-ionic fabric-conditioning surfactants, inwhich the total amount of components (a), (b) and (c) is between 2% and60% by weight in a manner such that, with respect to the total amount ofthe said components (a), (b) and (c), (i) the proportion by weight ofcomponent (a) is between 2% and 99%, (ii) the proportion by weight ofcomponent (b) is between 0% and 98%, (v) the proportion by weight ofcomponent (c) is between 0% and 40%, and (vi) the proportion by weightof the total amount of (b) and (c) is between 1% and 98%. 20.-Compositions according to claim 19, characterized in that the totalamount of components (a), (b) and (c) is between 3% and 40% by weight,(i) the proportion by weight of component (a) is between 3% and 80%,(ii) the proportion by weight of component (b) is between 0% and 97%,(v) the proportion by weight of component (c) is between 0% and 30%, and(vi) the proportion by weight of the total amount of (b) and (c) isbetween 20% and 97%.